To most people, the importance of helium does not extend beyond its ability to get party balloons to rise. Compared to fossil fuels, it is not usually thought of as a material that is critical for a technologically advanced society to function well. However, the use of helium in scientific, industrial and medical fields is critical. Moreover, similar to fossil fuels, helium is not an easily renewable resource. It will eventually become scarce. Efforts will have to be made to find new natural deposits of the gas. This may make it far more expensive to use for any but the most essential endeavors. The purpose of this paper is to review:
the origins of the 2nd element;
where it currently can be found (both terrestrially and extraterrestrially);
how it is acquired;
for what it is currently used;
whether or not there actually is a shortage.
Creation
Stellar
Helium was first discovered in 1868 by two astronomers who were working independently, Pierre Jules Jansen and Norman Lockyer. They determined its existence by examining the spectrum emission lines of the sun. One particularly bright yellow line was found that did not match any known elemental spectra at that time. This new element was named “helium” after “helios”, the Greek word for the sun. [Herman, 2012]
Almost all of the helium that exists in the universe was created through nucleosynthesis. However, competing theories have been proposed over the decades debating when its nucleosynthesis took place. If it happened during the first few minutes of the big bang, most of the helium that exists in stars is just recycled from that time. Else, it was created over the past 13 billons years in stellar nuclear reactions. In the 1950’s, it was thought that most of the helium was created during, or just a few minutes after, the big bang. Not enough time seemed to have passed for the calculated amount of the element to have been created just by hydrogen being converted to helium in stellar nuclear reactions. In addition, dimmer stellar luminosities and lower expected background energy levels seemed to confirm big bang origin theories. [Burbidge & Hoyle, 1998] In the later 50’s, contradicting theories were presented. These theories were based on relatively newer measurements of background radiation that seemed to indicate that energy levels were sufficient for mostly stellar created helium. In addition, universal density calculations seemed to indicate that the amount found closely match the amount expected. [Burbidge & Hoyle, 1998] However, recent studies indicate that most of the nucleosynthesis took place during the big bang, as originally thought. Measurements show that shortly after the big bang the cosmic temperature was about 1 billion K. During these first few minutes, enough energy was produced for protons and neutrons to fuse and create most of the universe’s helium. [Stellar helium.2003; Schmelz, 2003]
There was some concern regarding its isotopic ratio. Isotope 3He is created by nucleosynthesis. 4He is created radiogenically. Because of this, it was expected that the 3He isotope should be in abundance rather than 4He. When this was not found to be the case, it put the Big Bang theory of the origin of helium in question. In 2007, it was found that stars about one or 2 times our sun’s mass go through a process called “core flash” which was found to convert two 3He into a 4He and two hydrogen atoms. [Stephen Luntz, 2007]
Most current helium production in the universe is done by a series of proton collisions in the interior of stars. For much of time spent studying the nuclear reactions that take place in the cores of stars, it had been thought that it takes a star of about 5 to 7 solar masses to create elements heavier than helium. Smaller starts seemed to lack the gravitational energy. However, there is some speculation that stars that are even half a solar mass will create heavier elements. [Nelemans, 2007)]Younger stars, like our own, are composed of older stars that have ended their life cycles in catastrophic ways. The younger stars contain the remnant heavier elements created by those older stars. A consequence of this is those heavier elements can act as a catalyst to aid the creation of helium via a process called the CNO (carbon-nitrogen-oxygen) cycle. [Lyubimkov, 2010]
Radio active decay
Toward the end of 1800’s it was found that helium could be extracted from the gases produced from cleveite, a mineral containing uranium. [Lyubimkov, 2010] In 1895, Scottish chemist Sir William Ramsey found that boiling cleveite in weak sulfuric acid would release certain gases. [Herman, 2012] It was initially suggested that this gas possibly contained an allotrope of hydrogen. [Wolfenden, 1969] This was prior to spectral line analysis. Once this analysis was done, it was found that one of the gases had spectral lines that matched those recently found during spectral analysis of sunlight. These lines matched the element that had already been named helium. [The discovery of helium.1895]
Early experiments determined the helium production rate from uranium to be roughly 2 million grams per year per million kilograms of uranium. [Soddy, 1908] It was also discovered that helium could also be produced in huge quantities from radium. [Production of helium by radium,1912] Over time it was determined that much of the helium trapped in the earth’s mantle is radiogenic in origin. Many radioactive isotopes, including strontium, neodymium, lead and hafnium, contribute to its production during alpha decay. [Class & Goldstein, 2005]
During alpha decay, alpha particles are given off. [Herman, 2012] An alpha particle is composed of two protons and two neutrons and carries a +2 charge. It is essentially a helium nuclei or a helium atom missing two electrons (He+2). As the energetic alpha particle travels, it loses energy to its surroundings via collisions with other atoms. The collisions also allow it to gain electrons from those atoms and become a neutral helium atom.
Properties
The properties of helium vary from the mundane to the extraordinary. It is a monatomic, colorless, odorless gas at standard temperatures and pressures. It is the second most abundant element in the universe. Compared with air, it has as specific gravity of 0.341 and six times higher thermal conductivity. [Eversole, 1938; Snyder & Bottoms, 1930] Helium has the ability to diffuse through solid materials such as glass, especially at higher temperatures. [Origin of helium-rich natural gas,1930] The most prominent spectral line for helium has a wavelength of 587nm (yellow). [The discovery of helium,1895]
It was placed as the second element on the periodic table after it was determined to have two protons in its atomic nucleus. It was also placed in the noble gas family since it was found to have a full 1s orbital, and therefore no valence electrons. This causes it to be chemically inert when in the non-excited ground state. However, it is theorized that it may react in a manner similar to other noble gases that were also thought to be inert. [Gernot Frenking, 2000] Attempts have been made since the 1960’s create helium fluoride (HeFl2), but with no success yet. Diatomic excimers containing helium have been created. [Herman, 2012]
Temperature based studies have yielded some unusual properties. It has the lowest melting and boiling points of any element. [Herman, 2012] It is an extremely difficult gas to liquefy since it requires that the temperature be brought down to about 4 K at normal atmospheric pressure. [Metz, Wearner, & Evans, 1939] At 2 K, it becomes a zero viscosity superfluid with high thermal conductivity. [Herman, 2012] In its liquid form, it will “creep” up along the sides of its container even going outside and down the outer walls if allowed to. Solid helium is impossible to obtain at normal pressures regardless how low the temperature is brought, and its solid will not equilibrate with its vapor under any circumstances. [Satterly, 1936] In addition, its behavior is very close to that of an ideal gas. [McLennan, 1920]
Artificial atmospheres where helium is either abundant or completely absent seem to have no negative effects on healthy animals, as long as oxygen is available in suitable relative amounts. [Eversole, 1938]
Current Locations
Extraterrestrial
Helium is the second most abundant element, after hydrogen. A significant isotopic amount of it is 4H. [Lyubimkov, 2010] It is estimated that helium itself makes up about 27-30% of all matter in the universe. [Anonymous, 2003]
With regard to celestial bodies, helium and hydrogen make up about 98% of the matter contained in stars and nebula. [Lyubimkov, 2010] Generally, the stars that seem to contain a higher ratio of helium are of type O, B and A. These are relatively hot starts. [Lyubimkov, 2010] Stars rich in helium burn hotter and brighter than average, but are also shorter lived. [Anonymous, 2003]
Helium can be found in great amounts within our solar system. Our sun shows evidence of helium in prominence spectra and not on the calm surface. [Lyubimkov, 2010] Jupiter and Saturn consist mostly of hydrogen and helium. The atmospheres of these planets may have differing layers of varying helium/hydrogen composition that creates portions of greater luminosity. [Lorenzen, Holst, & Redmer, 2009] The atmosphere of Uranus is 26% helium by mass. [Herman, 2012]
Terrestrial
From the end of the 1800’s to the early 1900’s, helium had been detected in many locations terrestrially: in the air, in many types of minerals, in natural gases and even spring waters. In the United States, Texas seems to be a location where much of the natural gas has a relatively high content of helium. Canada also has regions that are rich in helium. [McLennan, 1920]
The origin of the helium that currently exists on (or in) earth depends on its isotope. 3He is leftover from the formation of the earth about 4 billion years ago. 4He is a byproduct of radioactive decay (as discussed above). [Manning, 2008] Currently there is much debate over how to interpret fluctuating 3He/ 4He ratios that have been found through Earth’s layers. Some researchers feel it indicates a layered convection system of Earth’s mantle where 3He is trapped deeper than 4He. Others think it points to a whole-mantle convection system and the ratios are indicative of a heat-helium-water interaction that is far more complicated. [Albarède, 2005)] It has been proposed that the heating of helium deeper in Earth’s crust may have aided in its diffusion and caused it to rise to higher levels in great quantities. It then cooled in pockets with other natural gases. [Origin of helium-rich natural gas. 1930]
It is estimated that radioactive decay creates thousands of tons of helium each year. [Nuttall, Clarke, & Glowacki, 2012] The majority of the gas obtained by refineries is in this byproduct form, which is then used commercially. [Kaplan, 2007] However, not all of it can be captured. Much of it naturally diffuses through the layers of Earth’s crust. Individual helium atoms move with enough speed to escape Earth’s gravitational pull when they make their way into the upper atmosphere. Once there, they are swept away by solar winds. [Rhodes, 2011] Because of this only 0.0005% of our atmosphere is composed of helium. [Herman, 2012]
Acquired
Currently, helium is obtained using a process called fractional distillation. [Herman, 2012] This process took decades to develop.
Original extraction plants, built around the 1910’s, liquefied the air to obtain helium. [Seibel, 1938] However, it was determined that helium could be found in natural gas deposits found in the ground. [The use of helium for aircraft purposes, 1919] Those original air liquefaction plants were modified to be used with natural gas. However, the process of getting pure helium was difficult. It took several modifications in the gas rectifying columns, along with the liquefaction process, to separate the gases and reach a purity of 87%. By the early 1920’s, a purity of 99% was obtained via continued improvements. These improvements even allowed for the re-purification of helium in airships that had allowed atmospheric gas to diffuse into their containers. [McLennan, 1920]
In the 1960’s, there was increased interest in trying to obtain helium from those natural gas plants where its concentration was initially considered too low to be practically extracted. This interest lead to the development of several types of semi-permeable materials. By passing the natural gas through pipes made of material only permeable helium, it could be obtained easily and cost effectively. [Stern, Sinclair, Gareis, Vahldieck, & Mohr, 1965]
The amount of helium obtained can vary. Locations where natural gas is mined in Europe contain a negligible amount. [McLennan, 1920] Mining locations in Texas and Colorado have up to 2% of the element in their natural gas deposits. [Metz, Wearner, & Evans, 1939] Some locations have reported as much as 7% helium by volume. [Herman, 2012] After this gas mixture is extracted, it is cooled to about 90K where the only substance that remains in a gaseous form is helium. [Kaplan, 2007]
Uses
In many fields, liquid helium is used as a refrigerant or coolant for various pieces of machinery. Helium was first liquefied in 1908 where it was then used in mercury superconductivity experiments. [Nuttall, Clarke, & Glowacki, 2012] Experiments in superconductivity require the use of magnets kept at extremely low temperatures which only liquid helium can provide. [Kaplan, 2007] Other experiments that require an environment close to absolute zero use helium for this purpose. [Helium warning, 2010] Helium’s thermo conductivity makes it an ideal heat transfer agent in gas-cooled nuclear reactors. [Rhodes, 2011]
In the later 1910’s, it was considered a desired replacement in airships since it was non-flammable and had 92% the lifting power of hydrogen. [McLennan, 1920] Another benefit was that it did not diffuse through the material of the airship as quickly as hydrogen. [The use of helium for aircraft purposes, 1919]
Helium’s inertness is taken advantage of in many fields. This property is optimal for use in gas chromatography since it is non-flammable and will not react with the analyte. It also has a wide range of flow rates. In some reactions, it is used as a blanket gas. This protects reactants from atmospheric oxygen and prevents unwanted byproducts. This also is used in welding metals to make stronger welds by preventing contact with atmospheric gases. [Rhodes, 2011] During a shuttle launch about a million cubic feet of gaseous helium is used to purge oxygen from the engines. [Kaplan, 2007]
It is also used in instances where health and safety are a concern. In these cases “heliox”, a mixture of oxygen and helium, is used. Divers are able to reach greater depths when using the mixture as their breathing supply. [Snyder & Bottoms, 1930] They are also able to stay under water longer and return to the surface faster without getting the bends. [Seibel, 1938] Research has been done for decades on the use of heliox as a ventilation gas for critically ill patients. [Eversole, 1938] The lower density of the gas mixture seems to ease respiratory effort and takes better advantage of the body’s oxygen exchange via pressure differential. [Gainnier & Forel, 2006] There have also been some heliox-based therapies for certain types of asthma and chronic obstructive pulmonary disease. Another health related usage is with deep tissue skin burns. Preliminary findings indicate that helium plasma flow speeds up healing times. It may also reduce inflammation and reduce chances of infection from burn injuries. [Yaskov et al., 2010]
There are also some innovative ideas being explored. Some aeronautic research is being done on a new aircraft paint containing cleveite. Since helium is inert, it does not react, or “stick”, to most other substances. However, cleveite is one of few substances that helium will readily stick to. This makes it a good candidate for a new aerodynamically efficient coating. [Helium coat could cut plane drag, 1998]
Shortage (?)
Since helium is an element, it is impossible to create more of it chemically. The only possible, synthetic, way to create more terrestrially would be via nuclear fusion. This would be extremely cost prohibitive and the amounts created would not be enough to put to practical use. It could potentially be extracted from the atmosphere, but this would also be very costly. [Nuttall, Clarke & Glowacki, 2012]
In some ways, this puts helium in the same class as fossil fuels. They are both produced by natural processes and it takes quite a while for a usable amount to be generated. Helium, however, is recyclable since it is not actually consumed by any of the processes in which it is used. [Rhodes, 2011] However, unlike oil or coal, helium is naturally escapes before any attempt is made at extracting it. Even when it is captured in a natural gas mixture, many refineries vent helium away in huge amounts. This issue may be addressed in the near future. Since the nation is relying more on electricity generated from natural gas, newer refineries can be ready built with helium extraction capabilities. [Nuttall, Clarke & Glowacki, 2012] Storage is not fool proof since helium will boil off if it sits around long enough in vacuum flasks. [Kaplan, 2007] It will even diffuse through the steel walls of gas storage cylinders. It has been found that a full cylinder left to sit untouched for about 6 months will have roughly half the amount of gas remaining. [Rhodes, 2011]
It had been brought to the attention of the scientific community that we may be facing a helium shortage that could affect the various scientific and industrial fields that depend on it. The source of this shortage seems to be related mostly to political and economic obstacles, and not to any natural lack of the gas. The real issue is that the government does not want to cover the cost of extracting it any more.
Up to the 1930’s, the US had the only known natural gas fields containing amounts of helium that could be practically extracted. Therefore, this created a monopoly with the US having the only plants supplying the gas. [Seibel, 1938] It naturally followed that the US became the first country to extract and store helium. In 1960s, the US government decided to start stockpiling by purchasing it from several private companies. [Nuttall, Clarke & Glowacki, 2012] In a series of amendments, called The Helium Act Amendments (HAA), the government provided incentives for private companies to sell their supplies to the federal government where it would be stored in an underground facility. That facility was operated by the U.S. Bureau of Land Management (BLM). The BLM would be allowed to borrow money from the government and repay the debt with the proceeds when the helium was later sold off. [Mascone, 2012] When the HAA was originally proposed, many scientist brought to attention the potential negative impact this law would have on the supply of the gas. The National Research Council (NRC) assured them that there would be no impact. The NRCs reasoning was that, despite there only being 10 years’ worth of gas in the reserve, the current demands for it were already being met by the few private suppliers. In addition, the council would attempt to focus on recycling and finding other sources. [Macilwain, 2000]
In 1996, it became evident that the BLM would not be able to repay its debt. Additionally, market demands changed over the years and helium use increased. The act had been found to have a negative impact on those fields that use much of this federally provided helium, particularly the scientific, biomedical and national security fields. [Mascone, 2012] In response to these issues, the federal government created a law ordering the privatization of its helium production. [Helium warning, 2010] This law, the Helium Privatization Act (HPA), required the selling off all but a small reserve of helium in an attempt to repay the dept. [Mascone, 2012] The HPA mandated the sale of federal helium by 2015. [Kaplan, 2007] Unfortunately, if the government sold off its entire supply it would hurt those who now depended on it. Either consumers would be completely cut off, or they would be at the mercy of the private market.
As of June of this year (2012), the Senate was working on passing legislation that would address this issue. The Helium Stewardship Act of 2012 would ensure that the drawdown of helium was done more gradually and that its pricing scheme was done transparently to ensure fair market value of the gas is maintained. [Mascone, 2012]
Burbidge, G., & Hoyle, F. (1998). The origin of helium and the other light elements. The Astrophysical Journal Letters, 509(1), L1-L3. http://dx.doi.org/10.1086/311756
Class, C. & Goldstein, S. L. (2005). Evolution of helium isotopes in the earth's mantle. Nature, 436(7054), 1107-1112. http://dx.doi.org/10.1038/nature03930
Gainnier, M., & Forel, J. (2006). Clinical review: Use of helium-oxygen in critically ill patients. Critical Care (London, England), 10(6), 241-241. http://dx.doi.org/10.1186/cc5104
Macilwain, C. (2000). Green light for plans to sell off US helium reserve. Nature, 405(6786), 496-496.http://dx.doi.org/10.1038/35014757
Manning, D. A. C. (2008). Where does all the helium that we use come from? Rapid Communications in Mass Spectrometry, 22(11), 1640-1642. http://dx.doi.org/10.1002/rcm.3452
Snyder, W. E., & Bottoms, R. R. (1930). Properties and uses of helium. Industrial & Engineering Chemistry, 22(11), 1189-1191. http://dx.doi.org/10.1021/ie50251a025
Stern, S. A., Sinclair, T. F., Gareis, P. J., Vahldieck, N. P., & Mohr, P. H. (1965). HELIUM RECOVERY BY PERMEATION. Industrial & Engineering Chemistry, 57(2), 49-60. http://dx.doi.org/10.1021/ie50662a008
Yaskov, I. M., Troshin, V. P., Kirillov, S. K., Korolyev, A. A., Martinovich, A. I., & Lavrenov, S. A. (2010). Use of helium plasma flow for healing deep burning wounds. Biomedical Engineering, 44(2), 76-77. http://dx.doi.org/10.1007/s10527-010-9160-2
Helium: Up, up…and away?
Introduction
To most people, the importance of helium does not extend beyond its ability to get party balloons to rise. Compared to fossil fuels, it is not usually thought of as a material that is critical for a technologically advanced society to function well. However, the use of helium in scientific, industrial and medical fields is critical. Moreover, similar to fossil fuels, helium is not an easily renewable resource. It will eventually become scarce. Efforts will have to be made to find new natural deposits of the gas. This may make it far more expensive to use for any but the most essential endeavors.The purpose of this paper is to review:
Creation
Stellar
Helium was first discovered in 1868 by two astronomers who were working independently, Pierre Jules Jansen and Norman Lockyer. They determined its existence by examining the spectrum emission lines of the sun. One particularly bright yellow line was found that did not match any known elemental spectra at that time. This new element was named “helium” after “helios”, the Greek word for the sun. [Herman, 2012]Almost all of the helium that exists in the universe was created through nucleosynthesis. However, competing theories have been proposed over the decades debating when its nucleosynthesis took place. If it happened during the first few minutes of the big bang, most of the helium that exists in stars is just recycled from that time. Else, it was created over the past 13 billons years in stellar nuclear reactions. In the 1950’s, it was thought that most of the helium was created during, or just a few minutes after, the big bang. Not enough time seemed to have passed for the calculated amount of the element to have been created just by hydrogen being converted to helium in stellar nuclear reactions. In addition, dimmer stellar luminosities and lower expected background energy levels seemed to confirm big bang origin theories. [Burbidge & Hoyle, 1998] In the later 50’s, contradicting theories were presented. These theories were based on relatively newer measurements of background radiation that seemed to indicate that energy levels were sufficient for mostly stellar created helium. In addition, universal density calculations seemed to indicate that the amount found closely match the amount expected. [Burbidge & Hoyle, 1998] However, recent studies indicate that most of the nucleosynthesis took place during the big bang, as originally thought. Measurements show that shortly after the big bang the cosmic temperature was about 1 billion K. During these first few minutes, enough energy was produced for protons and neutrons to fuse and create most of the universe’s helium. [Stellar helium.2003; Schmelz, 2003]
There was some concern regarding its isotopic ratio. Isotope 3He is created by nucleosynthesis. 4He is created radiogenically. Because of this, it was expected that the 3He isotope should be in abundance rather than 4He. When this was not found to be the case, it put the Big Bang theory of the origin of helium in question. In 2007, it was found that stars about one or 2 times our sun’s mass go through a process called “core flash” which was found to convert two 3He into a 4He and two hydrogen atoms. [Stephen Luntz, 2007]
Most current helium production in the universe is done by a series of proton collisions in the interior of stars. For much of time spent studying the nuclear reactions that take place in the cores of stars, it had been thought that it takes a star of about 5 to 7 solar masses to create elements heavier than helium. Smaller starts seemed to lack the gravitational energy. However, there is some speculation that stars that are even half a solar mass will create heavier elements. [Nelemans, 2007)]Younger stars, like our own, are composed of older stars that have ended their life cycles in catastrophic ways. The younger stars contain the remnant heavier elements created by those older stars. A consequence of this is those heavier elements can act as a catalyst to aid the creation of helium via a process called the CNO (carbon-nitrogen-oxygen) cycle. [Lyubimkov, 2010]
Radio active decay
Toward the end of 1800’s it was found that helium could be extracted from the gases produced from cleveite, a mineral containing uranium. [Lyubimkov, 2010] In 1895, Scottish chemist Sir William Ramsey found that boiling cleveite in weak sulfuric acid would release certain gases. [Herman, 2012] It was initially suggested that this gas possibly contained an allotrope of hydrogen. [Wolfenden, 1969] This was prior to spectral line analysis. Once this analysis was done, it was found that one of the gases had spectral lines that matched those recently found during spectral analysis of sunlight. These lines matched the element that had already been named helium. [The discovery of helium.1895]Early experiments determined the helium production rate from uranium to be roughly 2 million grams per year per million kilograms of uranium. [Soddy, 1908] It was also discovered that helium could also be produced in huge quantities from radium. [Production of helium by radium,1912] Over time it was determined that much of the helium trapped in the earth’s mantle is radiogenic in origin. Many radioactive isotopes, including strontium, neodymium, lead and hafnium, contribute to its production during alpha decay. [Class & Goldstein, 2005]
During alpha decay, alpha particles are given off. [Herman, 2012] An alpha particle is composed of two protons and two neutrons and carries a +2 charge. It is essentially a helium nuclei or a helium atom missing two electrons (He+2). As the energetic alpha particle travels, it loses energy to its surroundings via collisions with other atoms. The collisions also allow it to gain electrons from those atoms and become a neutral helium atom.
Properties
The properties of helium vary from the mundane to the extraordinary. It is a monatomic, colorless, odorless gas at standard temperatures and pressures. It is the second most abundant element in the universe. Compared with air, it has as specific gravity of 0.341 and six times higher thermal conductivity. [Eversole, 1938; Snyder & Bottoms, 1930] Helium has the ability to diffuse through solid materials such as glass, especially at higher temperatures. [Origin of helium-rich natural gas,1930] The most prominent spectral line for helium has a wavelength of 587nm (yellow). [The discovery of helium,1895]It was placed as the second element on the periodic table after it was determined to have two protons in its atomic nucleus. It was also placed in the noble gas family since it was found to have a full 1s orbital, and therefore no valence electrons. This causes it to be chemically inert when in the non-excited ground state. However, it is theorized that it may react in a manner similar to other noble gases that were also thought to be inert. [Gernot Frenking, 2000] Attempts have been made since the 1960’s create helium fluoride (HeFl2), but with no success yet. Diatomic excimers containing helium have been created. [Herman, 2012]
Temperature based studies have yielded some unusual properties. It has the lowest melting and boiling points of any element. [Herman, 2012] It is an extremely difficult gas to liquefy since it requires that the temperature be brought down to about 4 K at normal atmospheric pressure. [Metz, Wearner, & Evans, 1939] At 2 K, it becomes a zero viscosity superfluid with high thermal conductivity. [Herman, 2012] In its liquid form, it will “creep” up along the sides of its container even going outside and down the outer walls if allowed to. Solid helium is impossible to obtain at normal pressures regardless how low the temperature is brought, and its solid will not equilibrate with its vapor under any circumstances. [Satterly, 1936] In addition, its behavior is very close to that of an ideal gas. [McLennan, 1920]
Artificial atmospheres where helium is either abundant or completely absent seem to have no negative effects on healthy animals, as long as oxygen is available in suitable relative amounts. [Eversole, 1938]
Current Locations
Extraterrestrial
Helium is the second most abundant element, after hydrogen. A significant isotopic amount of it is 4H. [Lyubimkov, 2010] It is estimated that helium itself makes up about 27-30% of all matter in the universe. [Anonymous, 2003]With regard to celestial bodies, helium and hydrogen make up about 98% of the matter contained in stars and nebula. [Lyubimkov, 2010] Generally, the stars that seem to contain a higher ratio of helium are of type O, B and A. These are relatively hot starts. [Lyubimkov, 2010] Stars rich in helium burn hotter and brighter than average, but are also shorter lived. [Anonymous, 2003]
Helium can be found in great amounts within our solar system. Our sun shows evidence of helium in prominence spectra and not on the calm surface. [Lyubimkov, 2010] Jupiter and Saturn consist mostly of hydrogen and helium. The atmospheres of these planets may have differing layers of varying helium/hydrogen composition that creates portions of greater luminosity. [Lorenzen, Holst, & Redmer, 2009] The atmosphere of Uranus is 26% helium by mass. [Herman, 2012]
Terrestrial
From the end of the 1800’s to the early 1900’s, helium had been detected in many locations terrestrially: in the air, in many types of minerals, in natural gases and even spring waters. In the United States, Texas seems to be a location where much of the natural gas has a relatively high content of helium. Canada also has regions that are rich in helium. [McLennan, 1920]The origin of the helium that currently exists on (or in) earth depends on its isotope. 3He is leftover from the formation of the earth about 4 billion years ago. 4He is a byproduct of radioactive decay (as discussed above). [Manning, 2008] Currently there is much debate over how to interpret fluctuating 3He/ 4He ratios that have been found through Earth’s layers. Some researchers feel it indicates a layered convection system of Earth’s mantle where 3He is trapped deeper than 4He. Others think it points to a whole-mantle convection system and the ratios are indicative of a heat-helium-water interaction that is far more complicated. [Albarède, 2005)] It has been proposed that the heating of helium deeper in Earth’s crust may have aided in its diffusion and caused it to rise to higher levels in great quantities. It then cooled in pockets with other natural gases. [Origin of helium-rich natural gas. 1930]
It is estimated that radioactive decay creates thousands of tons of helium each year. [Nuttall, Clarke, & Glowacki, 2012] The majority of the gas obtained by refineries is in this byproduct form, which is then used commercially. [Kaplan, 2007] However, not all of it can be captured. Much of it naturally diffuses through the layers of Earth’s crust. Individual helium atoms move with enough speed to escape Earth’s gravitational pull when they make their way into the upper atmosphere. Once there, they are swept away by solar winds. [Rhodes, 2011] Because of this only 0.0005% of our atmosphere is composed of helium. [Herman, 2012]
Acquired
Currently, helium is obtained using a process called fractional distillation. [Herman, 2012] This process took decades to develop.Original extraction plants, built around the 1910’s, liquefied the air to obtain helium. [Seibel, 1938] However, it was determined that helium could be found in natural gas deposits found in the ground. [The use of helium for aircraft purposes, 1919] Those original air liquefaction plants were modified to be used with natural gas. However, the process of getting pure helium was difficult. It took several modifications in the gas rectifying columns, along with the liquefaction process, to separate the gases and reach a purity of 87%. By the early 1920’s, a purity of 99% was obtained via continued improvements. These improvements even allowed for the re-purification of helium in airships that had allowed atmospheric gas to diffuse into their containers. [McLennan, 1920]
In the 1960’s, there was increased interest in trying to obtain helium from those natural gas plants where its concentration was initially considered too low to be practically extracted. This interest lead to the development of several types of semi-permeable materials. By passing the natural gas through pipes made of material only permeable helium, it could be obtained easily and cost effectively. [Stern, Sinclair, Gareis, Vahldieck, & Mohr, 1965]
The amount of helium obtained can vary. Locations where natural gas is mined in Europe contain a negligible amount. [McLennan, 1920] Mining locations in Texas and Colorado have up to 2% of the element in their natural gas deposits. [Metz, Wearner, & Evans, 1939] Some locations have reported as much as 7% helium by volume. [Herman, 2012] After this gas mixture is extracted, it is cooled to about 90K where the only substance that remains in a gaseous form is helium. [Kaplan, 2007]
Uses
In many fields, liquid helium is used as a refrigerant or coolant for various pieces of machinery. Helium was first liquefied in 1908 where it was then used in mercury superconductivity experiments. [Nuttall, Clarke, & Glowacki, 2012] Experiments in superconductivity require the use of magnets kept at extremely low temperatures which only liquid helium can provide. [Kaplan, 2007] Other experiments that require an environment close to absolute zero use helium for this purpose. [Helium warning, 2010] Helium’s thermo conductivity makes it an ideal heat transfer agent in gas-cooled nuclear reactors. [Rhodes, 2011]In the later 1910’s, it was considered a desired replacement in airships since it was non-flammable and had 92% the lifting power of hydrogen. [McLennan, 1920] Another benefit was that it did not diffuse through the material of the airship as quickly as hydrogen. [The use of helium for aircraft purposes, 1919]
Helium’s inertness is taken advantage of in many fields. This property is optimal for use in gas chromatography since it is non-flammable and will not react with the analyte. It also has a wide range of flow rates. In some reactions, it is used as a blanket gas. This protects reactants from atmospheric oxygen and prevents unwanted byproducts. This also is used in welding metals to make stronger welds by preventing contact with atmospheric gases. [Rhodes, 2011] During a shuttle launch about a million cubic feet of gaseous helium is used to purge oxygen from the engines. [Kaplan, 2007]
It is also used in instances where health and safety are a concern. In these cases “heliox”, a mixture of oxygen and helium, is used. Divers are able to reach greater depths when using the mixture as their breathing supply. [Snyder & Bottoms, 1930] They are also able to stay under water longer and return to the surface faster without getting the bends. [Seibel, 1938] Research has been done for decades on the use of heliox as a ventilation gas for critically ill patients. [Eversole, 1938] The lower density of the gas mixture seems to ease respiratory effort and takes better advantage of the body’s oxygen exchange via pressure differential. [Gainnier & Forel, 2006] There have also been some heliox-based therapies for certain types of asthma and chronic obstructive pulmonary disease. Another health related usage is with deep tissue skin burns. Preliminary findings indicate that helium plasma flow speeds up healing times. It may also reduce inflammation and reduce chances of infection from burn injuries. [Yaskov et al., 2010]
There are also some innovative ideas being explored. Some aeronautic research is being done on a new aircraft paint containing cleveite. Since helium is inert, it does not react, or “stick”, to most other substances. However, cleveite is one of few substances that helium will readily stick to. This makes it a good candidate for a new aerodynamically efficient coating. [Helium coat could cut plane drag, 1998]
Shortage (?)
Since helium is an element, it is impossible to create more of it chemically. The only possible, synthetic, way to create more terrestrially would be via nuclear fusion. This would be extremely cost prohibitive and the amounts created would not be enough to put to practical use. It could potentially be extracted from the atmosphere, but this would also be very costly. [Nuttall, Clarke & Glowacki, 2012]In some ways, this puts helium in the same class as fossil fuels. They are both produced by natural processes and it takes quite a while for a usable amount to be generated. Helium, however, is recyclable since it is not actually consumed by any of the processes in which it is used. [Rhodes, 2011] However, unlike oil or coal, helium is naturally escapes before any attempt is made at extracting it. Even when it is captured in a natural gas mixture, many refineries vent helium away in huge amounts. This issue may be addressed in the near future. Since the nation is relying more on electricity generated from natural gas, newer refineries can be ready built with helium extraction capabilities. [Nuttall, Clarke & Glowacki, 2012] Storage is not fool proof since helium will boil off if it sits around long enough in vacuum flasks. [Kaplan, 2007] It will even diffuse through the steel walls of gas storage cylinders. It has been found that a full cylinder left to sit untouched for about 6 months will have roughly half the amount of gas remaining. [Rhodes, 2011]
It had been brought to the attention of the scientific community that we may be facing a helium shortage that could affect the various scientific and industrial fields that depend on it. The source of this shortage seems to be related mostly to political and economic obstacles, and not to any natural lack of the gas. The real issue is that the government does not want to cover the cost of extracting it any more.
Up to the 1930’s, the US had the only known natural gas fields containing amounts of helium that could be practically extracted. Therefore, this created a monopoly with the US having the only plants supplying the gas. [Seibel, 1938] It naturally followed that the US became the first country to extract and store helium. In 1960s, the US government decided to start stockpiling by purchasing it from several private companies. [Nuttall, Clarke & Glowacki, 2012] In a series of amendments, called The Helium Act Amendments (HAA), the government provided incentives for private companies to sell their supplies to the federal government where it would be stored in an underground facility. That facility was operated by the U.S. Bureau of Land Management (BLM). The BLM would be allowed to borrow money from the government and repay the debt with the proceeds when the helium was later sold off. [Mascone, 2012] When the HAA was originally proposed, many scientist brought to attention the potential negative impact this law would have on the supply of the gas. The National Research Council (NRC) assured them that there would be no impact. The NRCs reasoning was that, despite there only being 10 years’ worth of gas in the reserve, the current demands for it were already being met by the few private suppliers. In addition, the council would attempt to focus on recycling and finding other sources. [Macilwain, 2000]
In 1996, it became evident that the BLM would not be able to repay its debt. Additionally, market demands changed over the years and helium use increased. The act had been found to have a negative impact on those fields that use much of this federally provided helium, particularly the scientific, biomedical and national security fields. [Mascone, 2012] In response to these issues, the federal government created a law ordering the privatization of its helium production. [Helium warning, 2010] This law, the Helium Privatization Act (HPA), required the selling off all but a small reserve of helium in an attempt to repay the dept. [Mascone, 2012] The HPA mandated the sale of federal helium by 2015. [Kaplan, 2007] Unfortunately, if the government sold off its entire supply it would hurt those who now depended on it. Either consumers would be completely cut off, or they would be at the mercy of the private market.
As of June of this year (2012), the Senate was working on passing legislation that would address this issue. The Helium Stewardship Act of 2012 would ensure that the drawdown of helium was done more gradually and that its pricing scheme was done transparently to ensure fair market value of the gas is maintained. [Mascone, 2012]
References
http://cheminfo2012.wikispaces.com/file/view/316011.zip/385406294/316011.zip
http://cheminfo2012.wikispaces.com/file/view/316668.zip/385412372/316668.zip
http://cheminfo2012.wikispaces.com/file/view/315203.zip/385374158/315203.zip
http://cheminfo2012.wikispaces.com/file/view/00007611-193901000-00007.zip/389606654/00007611-193901000-00007.zip
http://cheminfo2012.wikispaces.com/file/view/315202.zip/383812816/315202.zip
http://cheminfo2012.wikispaces.com/file/view/315204.zip/385384656/315204.zip
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